Figure 8: Schematic diagram of macrophage EPO signalling in promoting acute inflammation resolution.

(a) During acute peritonitis, the respiratory burst in neutrophils and monocytes/macrophages induces a two-peak depletion of local O2, resulting in local hypoxia and an increase of HIF-1α, leading to a two-peak enhancement of local EPO. (b) The induced EPO further upregulates macrophage EPOR expression to activate macrophage EPO signalling. EPO increases macrophage phagocytosis of ANs and debris, and enhances macrophage migration to draining lymph nodes to promote inflammation resolution.